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The title says for itself.
There are a lot of interesting new features in Ubuntu. For example, after migrating into Ubuntu the most interesting feature for me was Centralized application installation via Synaptic (users do not need to search for an application, download it from somewhere, install it, and if it is pirated software to search keygens and stuffs like that).
What else could be added to the list?

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+1 since these are my exact reasons. Was gonna leave a response but this is exactly it. Elaboration on the performance... The entire OS does not become unresponsive when trying to access a network share.
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Dmitriy LikhtenAug 30 '10 at 17:25

I kind of hate apt-get but love it, I love how easy it is to find apps but i dislike building from source etc whilst in windows its all packaged so its nice and easy to remove stuff (which it isn't from stuff you've made from source - or am i missing something!)
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WillAug 7 '10 at 18:16

I'd have to agree with Helix too but apt-get was, by far, my favorite feature of *nix. The concept of using repositories to download free open source software with a single command was like magic.
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Evan PlaiceSep 16 '10 at 11:24

When doing a fresh install, most users are also attracted by the fact that (almost) everything works out of the box, whereas on Windows you have to spend dozens of hours trying to figure out which drivers you need, where to get them and to install them.

As someone who uses a lot of virtual machines for the development and testing of our own bespoke software, the biggest thing for me was the lack of 'activation'. I can create a new VM, install Ubuntu and start using it. No messing around with keys and no worries about activation.

It just makes the whole develop/test/deploy cycle a bit less painful. :-)

A few days using applications that they use in Windows: Firefox, Chrome, Thunderbird, OpenOffice, Songbird, Skype.
Thats why I advise to users before migrate into Linux, use as many as possible cross-platform applications in Windows.

After running XP & Windows 7, my six year old Sempron box is suddenly a fast system again.

I love having Unix command line tools available. In Windows, I was always mucking about with GnuWin32 or Cygwin. But they never seemed to really fit in.

"Hmmm, I think I want to start learning Scala". A simple apt-get and I'm off. Being able to install anything I need without having to track down the most recent download or worrying about viruses is priceless.

No more weekly checks if all installed software is up-to-date, downloading the latest updates and manually installing all the stuff. I have so much more spare time now to do other things than staring at those installation programs!